Rakitic is more reliable to shit the bed in the CL and provide nothing offensively.
It's like people really don't pay attention to his performances there at all. He was abysmal against Chelsea in the 1-1, pedestrian in our Chelsea/Roma wins, and then put in a horrorshow against Roma again. With him it's impossible to progress the ball and get it into more dangerous areas against a parked bus. Conversely, it's near impossible to build out the back with Rakitic against a team that actually presses high and closes down in our half.
The worst part is he can only even effectively exist in a 4-4-2, he gets utterly destroyed in a 4-3-3. So we're forced to play a formation that hurts Busquets, Messi, Iniesta, and Coutinho just to help out Rakitic (and Suarez). The idea that Raki is a better DM than Busquets is beyond laughable. Just cause he does a cleanup job and statpads simple ball recoveries in his 4-4-2 position, he never has been and never will be the true spine of the midfield. Rakitic in a 4-4-2 is a glorified janitor on the pitch. Without Busi, we are lost.